1. Field of the Invention
This invention relates generally to evaporative cooler structures and more particularly to a new and improved floor pan structure which forms the water reservoir in a cooler cabinet.
2. Description of the Prior Art
Evaporative coolers of the type having an air handler mounted within a cabinet for drawing ambient air into the cooler through wetter cooler pads and delivering the evaporatively cooled air to a point of use, have the necessary cooler operating water supply contained within the floor pan of the cooler cabinet. The water level within the floor pan is maintained at a predetermined level by a float controlled water inlet valve which is connected to a source of fresh water under pressure, such as a municipal water supply line. The float controlled water inlet valve operates to supply fresh make-up water to replace that lost by evaporation during operation of the cooler. A pump is mounted in the floor pan and operates to supply the water in the floor pan to the cooler's water distribution plumbing system which directs the pumped water to the tops of the cooler pads. The water so delivered to the pads will trickle down through the pads under the influence of gravity. The wet cooler pads will cool the air being drawn therethrough by the air handler in accordance with the well known evaporative principles, and the unevaporated water will drain from the cooler pads back into the floor pan for recirculation.
During such operation, the water, which inherently contains minerals, such as sodium and calcium chlorides and other impurities, will increase as to its concentration of those minerals due to the evaporation process. As the mineral concentration increases, the rate of precipitation will also increase which results in mineral deposits, or scaling, of the various cooler components, and this problem is of particular concern with respect to the damage it inflicts on the electric motors and associated electrical elements of the cooler.
In addition to the mineral build-up problem, other contaminants will collect in the water supply contained in the floor pan due to the air washing effect which occurs as a result of drawing ambient air through the wet cooler pads. A relatively large percentage of airborne pollen, dust, and the like, will be washed out of the ambient air as it passes through the cooler pads, and such contaminants will be carried by the water into the floor pan of the cooler cabinet. These contaminants are detrimental to useful cooler life and efficient cooler operation of course, and a major concern relating to such airborne contaminants is bacteria. Airborne bacteria, which is washed from the incoming air into the water supply contained in the cooler's floor pan, is responsible for musty odors, which often accompany the cooled air delivered to the point of use. Further, such bacteria is responsible for fungi, algae and other Thallophyta growths which can, and very often occur in evaporative coolers.
The floor pan structures which have been used in most evaporative coolers for many years are open top pan shaped structures having a flat bottom with an endless upstanding sidewall which suitably supports the corner posts of the cooler cabinet and the cooler pads. And, in the case of a downdraft type of evaporative cooler, i.e., one in which the cooled air is delivered downwardly from the cooler to a point of use, the floor pan will also have a riser duct mounted therein which serves as a support for the air handler and means for conducting the evaporatively cooled air out of the cooler.
Due to the flat bottom configuration of the prior art floor pans and the size required to support the upper portions of the cooler cabinets, such floor pans inherently contain far more water than is necessary for operation of the evaporative cooler. And, the water level in such floor pan structures must be of sufficient depth for proper operation of the cooler's pump. For example, a 6500 C.F.M. evaporative cooler, which is normally the largest residential cooler used, will have a floor pan water storage capacity of about 20 to 22 gallons. This is considerably more than is required in that in operation, the cooler of the above mentioned example will only hold approximately 3 gallons of water in its water distribution plumbing network and in its pads.
In addition to this overly large water supply contained in the prior art floor pans, they present a very large water surface area in that such pans are usually about 4 to 5 inches deep. Therefore, the cooler cabinet and its various components are continuously being subjected to the damaging effects of a water body having an excessively large surface area.
It will be appreciated from the above that evaporative coolers per se, and more particularly the water supply and the floor pan of prior art evaporative coolers become severly contaminated during operation of the cooler. This is well known in the art and thus manufacturers as well as installation personnel strongly recommend that the owners, or users of such coolers periodically drain the contaminated water from the floor pan, clean it and refill the floor pan with fresh water, and the more frequent that this servicing is accomplished, the better.
The prior art floor pans make such servicing difficult, in that a considerable surface area of the floor pan is under water during cooler operation. Thus, almost the entire inner surface of the floor pan must first be rinsed, usually with a pressurized water stream from a garden hose, to flush dirt and other loose contaminants from the corners, flat bottom surface, and effected vertical surfaces of the pan. Then those surfaces must be scrubbed, sometimes with a wire brush, to remove slime, caked mineral deposits, flaking paint and/or other coating materials, and rust. It is recommended that any exposed metal parts be recoated, such as with an asphalt based coating, and then the cooler is ready to be refilled with fresh water and put back into service.
To help overcome some of these problems associated with the prior art, automatic flushing, draining and water replacing devices have been proposed, and those devices are fully disclosed in U.S. Pat. Nos. 4,192,832; 4,255,361; 4,289,713; 4,333,887 and 4,361,522 which issued to Adam D. Goettl. In those patents, a relatively small reservoir tank is provided immediately below an opening provided in the flat bottom surface of the cooler's floor pan. This reservoir tank contains about one gallon of water, which in addition to the approximately 3 gallons in the cooler's plumbing supply network and pads, results in a substantial decrease in the water supply in comparison to the 20 or so gallons which constitutes the water supply of a cooler which is not provided with such a reservoir tank. Further, the reservoir tank has considerably less water surface area in comparison to the cooler's floor pan. The unevaporated water returning from the cooler pads to the reservoir tank will flow through the floor pan into the reservoir tank and the flushing, draining and water replacing device is contained in and associated with the reservoir tank so as to automatically dump the cooler's water supply and replace it with fresh water at predetermined intervals. This virtually overcomes all the above described problems associated with the prior art water supplies, floor pans and other components of the evaporative coolers.
Even with all of the advantages mentioned above, one problem still exists in evaporative coolers which are equipped with the automatic flushing and draining devices described above, and that problem is a direct result of the long used flat bottom prior art cooler floor pans. In theory, the water passing through those floor pans on its way to the reservoir tank will continuously rinse the floor pan and thus keep it clean and contamination free. In actual practice however, this is not the case. Prior art floor pans of evaporative coolers are not precision structures and their flat bottom surfaces are not truly flat, and they are not necessarily in a truly horizontal plane when the coolers are installed. This, along with the fact that returning water will not rinse all the surface area of the flat bottoms, can result in standing puddles of virtually stagnant water while other surface areas receive little or no rinsing.
Therefore, a need exists for a new and improved floor pan structure for use in evaporative coolers which helps overcome some of the problems and shortcomings of conventional prior art evaporative coolers, and contributes significantly to the effective operation of evaporative coolers equipped with the above mentioned automatic flushing and draining mechanisms.